Oxide Etching by Enhanced inductively couples plasma

초록

Low frequency weak magnetic field is applied axially to an inductively coupled plasma(ICP). Efficient power transfer from RF source to plasma is enhanced by the axial magnetic field. High aspect raio deep-sub-micron contact holes in BPSG have been etched by C4F8/Ar plasma. The role of deposition of polymeric precursors in the etching process is monitored. By means of appearance mass spectroscopy (AMS), the distributions of fluorocarbon ions (CFx+;x=1-3) and CFx radicals are measured as a function of magnetization frequency. The axial magnetic field is found to influence the densities of CFx+ ions and F and CFx radicals. X-ray photoelectron spectroscopy (XPS) shows that fluorocarbon polymer on BPSG layer strongly varies with the magnetization frequency. Contact holes of 0.1 um diameter with aspect ratio of 10 are successfully fabricated in this system